Oil composition

ABSTRACT

The invention relates to oil composition comprising 0.1 to 59.8% by weight of a triglyceride, 40 to 99.7% by weight of a diglyceride, 0.1 to 10% by weight of a monoglyceride and at most 5% by weight of a free fatty acid, wherein contents of ω3 type unsaturated acyl groups having at least 20 carbon atoms and monoenoic acyl groups in acyl groups constituting the diglyceride are 15 to 89.5% by weight and 10 to 84.5% by weight, respectively; and oral medicinal compositions and foods comprising such an oil composition.  
     The oil composition effectively develops physiological functions derived from ω3 type unsaturated fatty acids, such as inhibition of platelet aggregation, and is excellent in effect of facilitating combustion of body fat, oxidation stability, flavor and the like, and also excellent in flowability.

TECHNICAL FIELD

[0001] The present invention relates to an oil or fat (hereafterreferred to as “oil” merely) composition which effectively developsphysiological functions derived from ω3 type unsaturated fatty acidshaving at least 20 carbon atoms, such as inhibition of plateletaggregation, and is excellent in effect of facilitating combustion ofbody fat, oxidation stability, flowability, flavor and the like, andoral medicinal compositions and foods comprising such an oilcomposition.

BACKGROUND ART

[0002] In recent years, it has been clarified that diglycerides have anobesity-preventing effect, an effect to prevent an increase in weight,etc. (Japanese Patent Application Laid-Open Nos. 300828/1992, etc.), andit is attempted to incorporate these into various kinds of foods. It hasbeen reported that when a glyceride mixture containing diglycerides at ahigh concentration is used in an oil phase, an edible oil-in-water typeemulsion composition have a rich fatty feel and is good in flavor evenwhen a fat content is decreased (Japanese Patent No. 2848849)

[0003] On the other hand, it has been known that ω3 type unsaturatedfatty acids having at least 20 carbon atoms, such as docosahexaenoicacid (DHA) and eicosapentaenoic acid (EPA) are mainly contained in theform of triglyceride in fish oil and the like in plenty and haveeffective physiological activities such as anti-platelet aggregationproperty, antitumor activity, immune activation, antiallergic activity,improvement in brain function and improvement in visual function.

[0004] As oils highly containing such diglycerides and ω3 typeunsaturated fatty acids, there have been known, for example, a naturaloil that DHA among constitutive fatty acids of the oil is contained in aproportion of at least 60%, and the total content of diglycerides andmonoglycerides is at least 80% of the oil (Japanese Patent ApplicationLaid-Open No. 60181/1996), and the like.

[0005] However, the ω3 type unsaturated fatty acids having. at least 20carbon atoms are very poor in oxidation stability. When a ω3 typeunsaturated fatty acid is oxidized, the oxidized unsaturated fatty acidinvolves a problem that not only its physiological activity functionsare lost, but also the living body is adversely affected when such anunsaturated fatty acid is taken. In addition, an oil highly containingsuch a ω3 type unsaturated fatty acid has an unpleasant flavor derivedfrom its raw oil, and so a problem is offered when it is used in food inparticular. Further, ω3 type unsaturated fatty acids involve a problemthat when they are converted into their corresponding diglycerides, theviscosity of the resulting diglycerides becomes high, so that thephysiological activities of the ω3 type unsaturated fatty acids are hardto be developed.

[0006] It is therefore an object of the present invention to provide anoil composition which is good in flowability. hard to be oxidized andexcellent in flavor, effectively develops physiological activities of ω3type unsaturated fatty acids having at least 20 carbon atoms, and isexcellent in effect of facilitating combustion of body fat, and oralmedicinal compositions and foods comprising such an oil composition.

DISCLOSURE OF THE INVENTION

[0007] The present inventors have attracted attention to thecompositions of acyl groups constituting a diglyceride and found thatwhen a ω3 type unsaturated acyl group having at least 20 carbon atom anda monoenoic acyl group as acyl groups constituting a diglyceride arecontained in specified amounts in an oil composition comprising atriglycerides, diglyceride, monoglyceride and free fatty acid inspecified proportions, an oil composition which is hard to be oxidized,good in flowability and excellent in flavor, effectively developsphysiological activities of ω3 type unsaturated fatty acids, and isexcellent in effect of facilitating combustion of body fat is provided.

[0008] The present invention provides an oil composition comprising 0.1to 59.8% by weight (hereafter indicated merely by “%” of a triglyceride,40 to 99.7% of a diglyceride, 0.1 to 10% of a monoglyceride and at most5% of a free fatty acid, wherein contents of ω3 type unsaturated acylgroups having at least 20 carbon atoms and monoenoic acyl groups in acylgroups constituting the diglyceride are 15 to 89.5% and 10 to 84.5%,respectively.

[0009] The present invention also provides an oral medicinal compositioncomprising such an oil composition.

[0010] The present invention further provides a food comprising such anoil composition.

BEST MODE FOR CARRYING OUT THE INVENTION

[0011] In the present invention, no particular limitation is imposed onthe number of carbon atoms in acyl groups constituting the triglyceride.However, the number of carbon atoms is preferably 8 to 24, particularly16 to 22. The content of unsaturated acyl groups is preferably at least55%, more preferably at least 70%, particularly preferably at least 90%based on all the acyl groups in the triglyceride. The triglyceride canbe obtained from a vegetable oil such as soybean oil, rapeseed oil, palmoil, rice oil or corn oil, an animal oil such as beef tallow or fishoil, or a hardened oil, fractionated oil or random transesterified oilthereof. The content of the triglyceride in the oil compositionaccording to the present invention must be 0.1 to 59.8%, preferably 5 to55%. When the content of the triglyceride is 0.1 to 59.8%, and thecontent of the monoglyceride is 0.1 to 10%, unpleasant flavor derivedfrom the free fatty acid and raw oil can be masked to improve the flavorof the resulting oil composition and also the oxidation stabilitythereof.

[0012] In the present invention, the acyl groups constituting thediglyceride include ω3 unsaturated acyl groups having at least 20 carbonatoms in a proportion of 15 to 89.5% preferably 20 to 70%, particularlypreferably 25 to 65%, most preferably 50 to 65% based on all the acylgroups in the diglyceride and monoenoic acyl groups in a proportion of10 to 84.5%, preferably 12 to 45%, particularly preferably 12 to 35%,most preferably 14 to 25%. The term “ω3 type unsaturated acyl group” asused herein means an acyl group that a first unsaturated bond is locatedon the third carbon atom from a ω position when the positions ofunsaturated bonds are specified from the ω position, and that has atleast 2 unsaturated bonds. As the ω3 type unsaturated acyl groups havingat least 20 carbon atoms, are preferred eicosapentaenoyl anddocosahexaenoyl groups. The monoenoic acyl group is an acyl group havinga carbon-carbon double bond. As examples thereof, are preferredhexadecamonoenoyl, octadecamonoenoyl, eicosamonoenoyl anddocosamonoenoyl groups.

[0013] In the present invention, the acyl groups constituting thediglyceride preferably include ω6 type unsaturated acyl groups. The term“ω6 type unsaturated acyl group” as used herein means an acyl group thata first unsaturated bond is located on the sixth carbon atom from a ωposition when the positions of unsaturated bonds are specified from theω position, and that has at least 2 unsaturated bonds. When the ω6 typeunsaturated acyl groups are contained, development of drug intoxicationsuch as hemolysis and hemorrhage, which are caused by excess ingestionof the ω3 type unsaturated acyl groups, can be inhibited and developmentof the physiological activities of the ω6 type unsaturated acyl groupscan be facilitated. Examples of the ω6 type unsaturated acyl groupsinclude a linoleyl group (cis,cis-9.12-octadecadienoyl group), aγ-linolenyl group (all cis-6,9,12-octadecatrienoyl group) and anarachidonyl group (all cis-5,8,11,14-eicosatetraenoyl group), with thelinoleyl group being preferred. The content of the ω6 type unsaturatedacyl groups in all the acyl groups in the diglyceride is preferably 0.5to 75%, more preferably 0.5 to 50%, particularly preferably 1 to 25%,most preferably 1 to 15% in order to more remarkably develop theabove-described effects of the present invention.

[0014] The diglyceride can be obtained by an optional process such astransesterification of any of various oils such as fish oil and rapeseedoil containing ω3 type unsaturated acyl groups, monoenoic acyl groups,ω6 type unsaturated acyl groups, etc. with glycerol or esterification ofa fatty acid derived from such an oil with glycerol. Among theseprocesses, the former process is particularly preferred. The reactionmethod thereof may be either a chemical reaction method making use of analkali catalyst such as sodium methoxide, or the like or a biochemicalreaction method making use of a lipolytic enzyme such as lipase. Thecontent of such a diglyceride in the oil composition according to thepresent invention must be 40 to 99.7%, preferably 50 to 95%,particularly preferably 60 to 90%. When the content is 40 to 99.7%, thedevelopment of the physiological activities derived from the ω3 typeunsaturated fatty acids is facilitated, and the effect of facilitatingcombustion of body fat becomes excellent.

[0015] In the present invention, a glyceride polymer may preferably becontained in order to more improve the oxidation stability. Theglyceride polymer is a polymer obtained by intermolecular polymerizationof a glyceride such as a triglycerides diglyceride or monoglyceride (forexample, “Kagaku to Seibutu (Chemistry and Organism), Vol. 21, page 179,1983), and no particular limitation is imposed on the polymerizationdegree of the glyceride, the positions of fatty acid esters, the kindsof acyl groups constituting the fatty acid esters, etc. The content ofthe glyceride polymer in the oil composition is preferably 0.1 to 10%.more preferably 0.1 to 5%, particularly preferably 0.2 to 2% from theviewpoints of improvement in oxidation stability of the oil compositionand flavor. The amount of such a glyceride polymer can be controlled bysuitably controlling reaction temperature conditions and the like uponsynthesis of the glyceride polymer. The glyceride polymer can bedetermined by an HPLC process in which a gel permeation chromatographiccolumn is connected.

[0016] The content of the monoglyceride in the oil composition accordingto the present invention must be 0.1 to 10%, preferably 0.1 to 5% fromthe viewpoint of improvement in the flavor of the oil composition. Thecontent of free fatty acids must be at most 5%, preferably at most 2%from the viewpoint of improvement in the flavor of the oil composition.

[0017] The oil composition according to the present invention can beprepared by mixing the above-described components and suitablysubjecting the resulting mixture to heating, stirring and/or the like.Alternatively, the oil composition according to tho present inventioncan be obtained by fractionating triglycerides, diglycerides,monoglycerides, glyceride polymers, free fatty acids and the likeobtained by transesterification of an oil containing ω3 type unsaturatedacyl groups, ω6 type unsaturated acyl groups, monoenoic acyl groups andthe like, such as fish oil or rapeseed oils with glycerol, and thensuitably mixing these fractionation products with one another. The oilcomposition according to the present invention can also be obtained bysubjecting the reaction product obtained according to theabove-described preparation process of the diglyceride to ordinarypurification treatments such as molecular distillation, deodorizing anddecolorizing.

[0018] The oil composition thus obtained has excellent physiologicalactivities such as effects of facilitating combustion of body fat,reducing blood sugar value, consuming triglyceride in blood, reducinginsulin in blood, improving liver function, reducing blood pressure, andinhibiting activation of plasminogen in addition to inhibitory effect onplatelet aggregation, is good in digestibility because it is excellentin flowability, can be stored over a long period of time because it isexcellent in oxidation stability, and moreover is excellent in flavor.In particular, since the ω3 type unsaturated acyl groups having at least20 carbon atoms are present as acyl groups constituting the diglyceride,the oil composition acts at a lower concentration than the case wherethey are present as free fatty acids, and so it has good fast-actingproperty, and is good in flavor and safe. Since the oil compositionaccording to the present invention has such excellent properties, it canbe utilized for oral medicinal compositions and foods.

[0019] No particular limitation is imposed on the forms of the oralmedicinal compositions, and examples thereof include solid preparationssuch as powder preparations, granule preparations, capsule preparations,pill preparations and tablet preparations; and liquid preparations suchas aqueous preparations, suspension preparations and emulsionpreparations. Such an oral preparation can be prepared by adding anexcipient, a disintegrant, a binder, a lubricants a surfactant, analcohols water, a water-soluble polymer, an sweet flavor, a tastecorrigent, an acid flavor and/or the like commonly used according to theform of the oral preparation in addition to the oil composition inaccordance with a method known per se in the art. Examples of oralmedicinal compositions include platelet aggregation inhibitors, bodyweight-reducing agents, brain function improvers, visual functionimprovers and diabetes improvers. It is preferred that the amount of theoil composition according to the present invention to be incorporated inthe oral medicinal composition be generally 0.1 to 100%, particularly 1to 80% though it varies according to the application and form of theoral medicinal composition. The oral medicinal composition is preferablyadministered in a dose of 0.1 to 50 g per day in terms of the oilcomposition. Meanwhile, the administration may be once per day, or maybe divided into several times per day.

[0020] With respect to the foods, the oil composition may be used asoil-containing foods containing the oil composition as a part of food.Examples of such oil-containing foods include healthy foods that thespecified functions are exhibited to promote health. Specific examplesthereof include tablet preparations, granule preparations, dressingssuch as French dressing, mayonnaises, creams, bakery foods such as breadand cookie, confectionery such as chocolates and potato chips, anddrinks, in which such an oil composition is incorporated. Suchoil-containing food can be produced by adding food materials commonlyused according to the kind of the oil-containing food in addition to theoil composition in accordance with a method known per se in the art. Itis preferred that the amount of the oil composition according to thepresent invention to be incorporated in food be generally 0.1 to 100%,particularly 1 to 80% though it varies according to the kind of thefood. It may also be used as a food material of oils for fried foodssuch as tempura and fries, or oils for frizzled foods.

EXAMPLES Example 1

[0021] Fish oil (product of Kao Corporation; 200 parts by weight) andglycerol (product of Wako Pure Chemical Industries, Ltd.; 8 parts byweight) were mixed with each other, and an alkali catalyst (sodiummethoxide, CH₃ONa; 0.6 parts by weight) was mixed to the resultantmixture to conduct transesterification at 100° C. for 4 hours underreduced pressure (0.133 kPa). The reaction product thus obtained wasfractionated by column chromatography on silica gel, and a triglyceride(56.1 parts by weight), a diglyceride (42.9 parts by weight) and amonoglyceride (1.0 part by weight) among the resultant fractionationproducts were mixed with one another to prepare Oil Composition 1.

Example 2

[0022] A triglyceride (56.0 parts by weight), a diglyceride (42.7 partsby weight), a monoglyceride (1.1 parts by weight) and a glyceridepolymer (0.2 parts by weight) among the respective fractionationproducts obtained in Example 1 were mixed with one another to prepareOil Composition 2.

Example 3

[0023] A high DHA-containing oil (“DHA-45”, product of MARUHA CORP.; 200parts by weight) and glycerol (10 parts by weight) were mixed with eachother to conduct transesterification and fractionation of respectivecomponents in a similar manner to Example 1. A triglyceride (10.3 partsby weight), a diglyceride (87.4 parts by weight), a monoglyceride (1.9parts by weight) and a glyceride polymer (0.4 parts by weight) were thenmixed with one another to prepare Oil Composition 3.

Comparative Examples 1 and 2

[0024] Rapeseed oil (product of Nisshin Oil Mills, Ltd.) and fish oilwere provided as Oil Composition 4 (Comparative Example 1) and OilComposition 5 (Comparative Example 2).

Comparative Example 3

[0025] Rapeseed oil (200 parts by weight) and glycerol (10 parts byweight) were mixed with each other to conduct transesterification andfractionation of respective components in a similar manner to Example 1.A triglyceride (21.7 parts by weight), a diglyceride (76.5 parts byweight), a monoglyceride (1.3 parts by weight) and a free fatty acid(0.5 parts by weight) were then mixed with one another to prepare OilComposition 6.

Comparative Example 4

[0026] A high DHA-containing oil (100 parts by weight), hydrogenatedcoconut oil (product of Kao Corporation; 100 parts by weight) andglycerol (8 parts by weight) were mixed with each other to conducttransesterification and fractionation of respective components in asimilar manner to Example 1. A triglyceride (41.6 parts by weight) and adiglyceride (58.4 parts by weight) were then mixed with each other toprepare Oil Composition 7.

Comparative Example 5

[0027] A triglyceride (56.7 parts by weight) and a diglyceride (43.7parts by weight) among the respective fractionation products obtained inExample 1 were mixed with cach other to prepare Oil Composition 7.

Example 4

[0028] A high DHA-containing oil (“DHA-45”, product of MARUHA CORP.; 100parts by weight) and glycerol (40 parts by weight) were mixed with eachother, and sodium methoxide (0.3 parts by weight) was mixed to theresultant mixture to conduct transesterification at 100° C. for 4.5hours under reduced pressure (0.266 to 0.399 kPa). The resultantreaction product was subjected to molecular distillation, treatment withcitric acid and then decolorizing treatment with activated carbon,further washed with water and deodorized (subjected to steaming). Thepurified product (Oil Composition 9) thus obtained had a composition:triglyceride 44.9% by weight: diglyceride 54.2% by weight; monoglyceride0.6% by weight; free fatty acid 0.1% by weight; and glyceride polymer0.2% by weight.

[0029] Principal fatty acid compositions of diglyceride fractionsderived from the respective oils obtained in Examples 1, 3 and 4 andComparative Examples 3 and 4 are shown in Table 1. TABLE 1 Example Comp.Example 1 3 4 3 4 ∞3 C18:3 0 0 0 10.3 0 C20:5 15.2 6.7 6.7 0 3.8 C22:68.4 46.3 46.3 0 24.1 Monoenoic C16:1 9.1 3.4 3.4 0 1.5 C18:1 4.3 10.510.5 49.8 4.8 C20:1 5.5 1.4 1.4 0 0.5 C22:1 5.2 1.1 1.1 0 0.3 ∞6 C18:22.0 1.3 1.3 29.1 0.6 C18:3 1.3 0.7 0.7 0 0.3 Saturated C16:0 0 0 0 022.8 C14:0 5.8 2.2 2.2 0 9.6 C16:0 16.9 11.3 11.3 8.1 10.2 c18:0 3.5 2.72.7 2.7 7.4

Test Example 1 Investigation of Inhibitory Effect on PlateletAggregation

[0030] Wistar mall rats aged 10 weeks were divided into 9 groups, and afeed containing rapeseed oil (10%) and one (3%) of Oil Compositions 1 to9 was given to its corresponding group for 2 weeks. Blood was thencollected from each rat to determine the inhibitory effect of each testcomposition on platelet aggregation in accordance with the methoddescribed in J. Nutri. Vol. 124, page 1898 (1994). The results are shownin Table 2. In the table, the numerical values indicate relative valuesthat a value in the case where Oil Composition 4 was used was regardedas 100. The smaller relative value indicates that platelet is harder toaggregate. TABLE 2 Oil Composition Relative value 1 81 2 81 3 64 4 100 595 6 106 7 93 9 69

[0031] Oil Compositions 1 to 3 exhibited a plateletaggregation-inhibiting effect superior to Oil Compositions 4 to 7.Particularly excellent effect was achieved in the case where among thesecompositions, Oil Compositions 3 and 9. in which the content of the ω3type unsaturated acyl groups in all the acyl groups in the diglyceridewas at least 50%, were each used.

Test Example 2

[0032] Wistar mail rats aged 10 weeks were divided into 3 groups eachcontaining 8 rats, and a feed having a composition shown in Table 3 wasgiven to each group for 2 weeks. After the rats were starved for 18hours, blood was collected through an abdominal aorta of each rat underether anesthesia to conduct a biochemical test of the blood. At the sametime, liver and peritoneal adipose tissues were taken out of the rat tomeasure their weight. Thereafter, a portion (0.5 g) thereof washomogenized by means of a glass homogenizer in a mixed solvent (10 mL)of chloroform and methanol (1:1) and filtered with suction through glassfiber filter paper (GA100, 47 mm).

[0033] Physiological saline was added to the filtrate and the mixturewas moderately stirred and then centrifuged (3000 rpm) for 10 minutes toconduct phase separation. A lower layer was taken out and dried to solidunder a nitrogen stream. The resultant solid was dissolved again in aproper amount of n-hexane and the solution was dried over anhydroussodium sulfate. The solvent was removed and the residue was dried tosolid under a nitrogen stream again. The resultant solid was dissolvedin 2-popanol (5 mL) to provide a test solution for lipid quantitativeanalysis.

[0034] A body fat ratio was measured by a body fat meter (EM-SCAN SA-2,product of Central Kagaku Boueki) for small animal.

[0035] Triglyceride contents in the blood, liver, and perirenal adiposetissues were determined by a Triglyceride Test Wako (manufactured byWako Pure Chemical Industries, Ltd.). A total cholesterol quantity inthe liver was determined by a Cholesterol E Test Wako (manufactured byWako Pure Chemical Industries, Ltd.). GPT (glutamic oxaloacetictransaminase) activity and GPT (glutamic pyruvic transaminase) activityin the blood were determined by separating sera and then using asparticacid and alanine as substrates, respectively, in accordance with theKarmen method (J. Clin. Invest., Vol. 34, page 131 (1955)). The resultsare shown in Table 4. TABLE 3 Control Test group (%) Casein 20 20   Cornoil 10 10   Oil 0  3^(*1) Mineral mixture 4  4   Vitamin mixture 1  1  Cellulose 4  4   Choline chloride 0.15  0.15 Starch 60.85 57.85

[0036] TABLE 4 TG TG content TG Result con- in peri- con- Total(relative Body tent renal tent cholesterol value) fat in adipose incontent in Control = 100 ratio liver tissues blood GOT GPT lever Cornoil 10%, 100 100 100 100 100 100 100 Comp. Ex. (Control) Corn oil + 101118 104 115 127 116 105 Oil Comp'n 6 Comp. Ex. Corn oil + 80 37 86 71 6359 87 Oil Comp'n 9 Example

[0037] It is understood from the results shown in Table 4 that in thegroup that the feed obtained by adding the oil composition (3%)according to the present invention to corn oil (10%) was ingested,excellent body fat-reducing effect is achieved, and the triglyceridecontent in perirenal adipose tissues, the triglyceride content in theliver, the total cholesterol content in the liver, the serumtransaminase levels (GOT, GPT) and the triglyceride content in the bloodcan also be reduced

Test Example 3

[0038] Oil Composition 9 charged into a soft capsule was ingested by 3healthy men (A, B and C) for 6 weeks in a dose of 1 g per day withoutchanging their eating habits to measure their BMI [Body Mass Index:(weight kg)/(height m×height m)], body fat ratio and waist sizes. Theresults are shown in Table 5. TABLE 5 After 0 week After 6 weeks A: BMI25.0 24.7 aged 39 years Body fat ratio (*) 25.1 24.2 Waist (cm) 88.287.0 B: BMI 23.8 23.3 aged 36 years Body tat ratio (%) 24.0 23.5 Waist(cm) 85.7 84.9 C: EMI 24.1 23.4 aged 32 years Body fat ratio (%) 24.724.1 Waist (cm) 87.6 86.1

[0039] It is understood from the results shown in Table 5 that when theoil composition according to the present invention is ingested, the bodyfat ratio can be reduced without changing the eating habit, andcorrespondingly BMI and waist size can be reduced.

Test Example 4

[0040] Ten healthy men having BMI of at least 24 (body fat ratio of atleast 23%; light obesity) were got to orally ingest Oil Composition 9molded in the form of a capsule in a dose of 2 g per day to determinetheir insulin concentrations in blood before beginning of the ingestionand after completion of the ingestion. As a result, the average value ofthe insulin concentrations in blood was 16.3 μU/mL before beginning ofthe ingestion (initial value), while the value was markedly reduced to12.9 μU/mL after completion of the ingestion (1 month) (p<0.05). Fromthis result, it was confirmed that the oil composition according to thepresent invention can significantly reduce the insulin concentration inblood.

Test Example 5

[0041] Oil Composition 9 charged into a soft capsule was ingested by 3men (A, B and C) having a fasting blood sugar level of 120 mg/dl or morefor 3 months in a dose of 2 g per day without changing their eatinghabits. Thereafter, their blood sugar levels were measured by a GlucoseTest Wako (manufactured by Wako Pure Chemical Industries, Ltd.). Theresults are given in Table 6. From the results, it was indicated thatthe blood sugar levels of all the men were reduced. It was confirmed bythis result that the blood sugar reducing agents according to thepresent invention are useful in reducing a blood sugar level and furtherin preventing and improving diabetes. TABLE 6 Initial value After 3months A: aged 39 years 123 101 B: aged 45 years 135 110 C: aged 42years 142 103

Test Example 6 Investigation of Oxidation Stability of Oil Composition

[0042] With respect to Oil Compositions 1 to 3, 5, 8 and 9, theinduction time was determined in accordance with the following method(CDM test version: standard oils and fats analyzing test method (editedby The Japan Oil Chemists' society). More specifically, while a samplewas heated to 90° C. in a reaction vessel, clean air was introduced tocollect volatile decomposition products formed by oxidation in water,thereby measuring the time (hr) up to a turning point where the electricconductivity of water rapidly changed. The results are shown in Table 7.In the table, the numerical values indicate relative values that thetime up to the turning point of Oil Composition 5 was regarded as 100.The greater relative value indicates that the oxidation stability isbetter. TABLE 7 Oil Composition Relative value 1 103 2 125 3 128 5 100 894 9 133

[0043] Oil Composition 1 to 3 and 9 were superior In oxidation stabilityto Oil Compositions 5 and 8.

Test Example 8 Investigation of Flowability of Oil Composition

[0044] With respect to Oil Compositions 1 to 3, 7 and 9, the viscositywas measured by means of an oscillational viscometer (40° C., 50 Hz).The results are shown in Table 8. TABLE 8 Oil Composition Viscosity (mPa· s) 1 61 2 62 3 45 7 105 9 40

[0045] Oil Compositions 1 to 3 and 9 had a viscosity not higher than 100mPa·s, and it was confirmed that the viscosity of an oil can be reducedto 100 cp or lower by containing monoenoic acyl groups in a proportionof at least 10% based on all the acyl groups in the diglyceride. Theviscosity is reduced to 100 mPa·s, preferably 70 mPa·s, whereby micelleof bile acid is easily formed upon ingestion of the resulting oilcomposition, and so the digestion of the oil composition is improved,and the development of the physiological activities is facilitated.

Test Example 9 Evaluation of French Dressing Containing Oil Composition3, 4, 8 or 9 as to Flavor

[0046] An oil composition-containing French dressing was prepared inaccordance with its corresponding formulation shown in Table 9 toevaluate it as to flavor. More specifically, wine vinegar was mixed withcommon salt, pepper and mustard. Its corresponding Oil Composition andsalad oil were added to the resultant mixture while stirring by awhipper. The resultant mixture was sufficiently stirred to prepare aFrench dressing. The dressing was put on coleslaw to evaluate it as toflavor by ten panelists in accordance with the following evaluationstandard. The average values of evaluation scores are shown in Table 9.TABLE 9 Test No. 1 2 3 4 Salad oil 30.0 30.0 30.0 30.0 Wine vinegar 50.050.0 50.0 50.0 Common salt 2.5 2.5 2.5 2.5 Pepper 0.6 0.6 0.6 0.6Mustard 0.5 0.5 0.5 0.5 Oil Composition 3 60.0 — — — Oil Composition 4 —60.0 — — Oil Composition 8 — — 60.0 — Oil Composition 9 — — — 60.0Average value of flavor 3.2 3.5 1.7 3.2

[0047] The French dressings using Oil Compositions 3 and 9,respectively, had substantially the same excellent flavor as that usingOil Composition 4. Belching after ingestion had no unpleasant feel. Onthe other hand, the French dressing using Oil Compositions 8 was poor inflavor, and belching after ingestion had an unpleasant feel.

Test Example 10 Evaluation of Oral Syrup Preparation Containing OilComposition 1, 2, 3, 4, 8 or 9 as to Flavor

[0048] An oral syrup preparation was prepared in accordance with itscorresponding formulation shown in Table 10. More specifically, aftersodium benzoate and purified sucrose were added to a proper amount ofheated purified water into a solution, hydroxypropyl cellulose wasadded, and the mixture was stirred by a homomixer into a solution,thereby preparing Liquid A. On the other hand, sucrose fatty acid esterwas dispersed in its corresponding Oil Composition to prepare Liquid B.Liquid B was added while stirring Liquid A by the homomixer, andpurified water was added thereto, thereby formulating an oral syruppreparation. The syrup preparations thus obtained were evaluated as toflavor in the same manner described in Test Example 9. The results areshown in Table 10.

[0049] As described above, the oil compositions according to the presentinvention are hard to be oxidized because the content of the ω3 typeunsaturated acyl group-containing diglyceride is relatively low, isexcellent in flavor and can effectively exhibit the physiologicalactivities of ω3 type unsaturated fatty acids. TABLE 10 Test No. 5 6 7 89 10 Hydroxypropyl 0.5 0.5 0.5 0.5 0.5 0.5 cellulose Purified sucrose50.0 50.0 50.0 50.0 50.0 50.0 Sucrose fatty 0.2 0.2 0.2 0.2 0.2 0.2 acidester Na benzoate 0.06 0.06 0.06 0.06 0.06 0.06 Oil Composition 1 5.0 —— — — — Oil Composition 2 — 5.0 — — — — Oil Composition 3 — — 5.0 — — —Oil Composition 4 — — — 5.0 — — Oil Composition 8 — — — — 5.0 — OilComposition 9 — — — — — 5.0 Purified water 44.24 44.24 44.24 44.24 44.2444.24 Average value of 3.1 3.1 3.4 3.7 2.2 3.5 flavor

[0050] The oral syrup preparations using Oil Compositions 1, 2, 3 and 9,respectively, had substantially the same excellent flavor as that usingOil Composition 4. Belching after ingestion had no unpleasant feel. Onthe other hand, the oral syrup preparation using Oil Compositions 8 waspoor in flavor, and belching after ingestion had an unpleasant feel.

[0051] Industrial Applicability

[0052] The oil compositions according to the present invention are hardto be oxidized, good in flowability and excellent in flavor, caneffectively develop physiological activities of ω3 type unsaturatedfatty acids having at least 20 carbon atoms, and are excellent in effectof facilitating combustion of body fat.

1. An oil composition comprising 0.1 to 59.8% by weight of atriglyceride, 40 to 99.7% by weight of a diglyceride, 0.1 to 10% byweight of a monoglyceride and at most 5% by weight of a free fatty acid,wherein contents of ω3 type unsaturated acyl groups having at least 20carbon atoms and monoenoic acyl groups in acyl groups constituting thediglyceride are 15 to 89.5% by weight and 10 to 84.5% by weight,respectively.
 2. The oil composition according to claim 1, which furthercomprises 0.1 to 10% by weight of a glyceride polymer.
 3. The oilcomposition according to claim 1 or 2, wherein the content of ω6 typeunsaturated acyl groups in acyl groups constituting the diglyceride is0.5 to 75% by weight.
 4. An oral medicinal composition comprising theoil composition according to any one of claims 1 to
 3. 5. A foodcomprising the oil composition according to any one of claims 1 to 3.